它是什么

Created: November-22, 2018

允许在声明变量时使用本地类型推断。

什么是类型推断？

你可以在不明确声明数据类型的情况下声明局部变量。编译器根据其初始化表达式的类型推断变量的数据类型。

选项推断 ：

Dim aString  = "1234" '--> Will be treated as String by the compiler
Dim aNumber  = 4711   '--> Will be treated as Integer by the compiler

与显式类型声明：

'State a type explicitly
Dim aString as String = "1234"
Dim aNumber as Integer = 4711

选项推断关闭：
Option Infer Off 的编译器行为取决于此处已记录的 Option Strict 设置。

Option Infer Off - Option Strict Off
所有没有显式类型声明的变量都声明为 Object。
```
Dim aString  = "1234" '--> Will be treated as Object by the compiler
```
选项推断关闭 - 选项严格打开
编译器不允许你声明没有显式类型的变量。
```
'Dim aString  = "1234" '--> Will not compile due to missing type in declaration
```